Is it possible to change/amend a submission?

Can I change an already existing submission? I know I can create a new submission, but this probably will be double work for the reviewers. The solution itself is the same, I just want to improve the presentation.

You are welcome to submit as many answers as you want, including multiple answers to the same problem.

Some participants submitted an answer and then a few days later had an idea on how to improve it. All of these are welcome.

The only limitation is that for any given problem we will pick your best solution (e.g. you cannot win both first and second prize for any given problem)

Thank you, I see. Still, is it possible to withdraw a solution?

The only motivation here is to make the job of the reviewers easier – I know that my second submission will make my first one obsolete, so I’d rather have the first one removed.

sure, no problem. We’ll do what you ask.